Urban Forestry & Urban Greening 23 (2017) 113–124 Contents lists available at ScienceDirect Urban Forestry & Urban Greening journal homepage: www.elsevier.com/locate/ufug Original article Influence of changing trees locations on thermal comfort on street parking lot and footways Dragan D. Miloˇ sevi ´ c a,∗ , Ivana V. Bajˇ sanski b , Stevan M. Savi ´ c a a Climatology and Hydrology Research Centre, Faculty of Sciences, University of Novi Sad, Trg Dositeja Obradovi´ ca 3, 21000 Novi Sad, Serbia b Department of Architecture and Urban Planning, Faculty of Technical Sciences, University of Novi Sad, Trg Dositeja Obradovi´ ca 6, 21000 Novi Sad, Serbia a r t i c l e i n f o Article history: Received 24 August 2016 Accepted 4 March 2017 Available online 12 March 2017 Keywords: Ladybug software Outdoor thermal comfort Street parking lot Tree location UTCI a b s t r a c t Locations of trees in street parking lots (SPL) impact outdoor thermal comfort and should be considered during the urban planning process. In this paper we developed a procedure for changing trees locations in order to improve outdoor thermal comfort on SPL and associated footways. Furthermore, a sensitiv- ity test on the effect of different tree crown shapes on outdoor thermal comfort was carried out. We applied theprocedure on real-world SPL design in the City of Novi Sad (Serbia). A temporal analysis is performed for the heat wave period using Universal Thermal Climate Index (UTCI) calculations in the Ladybug software. The results showed improvement of outdoor thermal comfort on 77 % of all body locations in proposed SPL design with predetermined number of trees. The largest outdoor thermal comfort improvement was noticed in the afternoon hours with up to 3.3 ◦ C UTCI decrease on single body location. By adding trees to the SPL, heat stress was reduced on 84 % of all body locations with maximal UTCI decrease of 3.7 ◦ C on single body location. Furthermore, heat stress reduction by cylinder-shaped tree crowns showed to be more pronounced compared to the sphere-shaped and the cone-shaped tree crowns. Proposed procedure showed that the locations of trees as well as tree crown shapes are very important for the improvement of outdoor thermal comfort and creation of environmentally conscious SPL design. © 2017 Elsevier GmbH. All rights reserved. 1. Introduction Parking areas are associated with higher air temperatures (T) (Aniello et al., 1995; Ca et al., 1998) as a consequence of its artificial impervious surface and lower proportion of vegetation cover. In order to improve outdoor thermal comfort at parking areas, usage of vegetation is recommended. Urban vegetation reduces parking space temperature during summer months (Akbari et al., 1997; Asaeda et al., 1996) leading to more comfortable open urban spaces (Gillner et al., 2015; Klemm et al., 2015; Mullaney et al., 2015). This Abbreviations: UTCI, universal thermal climate index; SPL, street parking lot; T, air temperature; RH, relative humidity; v, wind speed; g, longwave and short- wave radiation fluxes; UTC, universal time coordinated; LCZ, local climate zone; HRE, height of roughness elements; SVF, sky view factor; BSF, building surface factor; ISF, impervious surface factor; PSF, pervious surface factor; ALB, albedo; WRF, weather research and forecasting; NOAA/NCEP GFS, National Oceanic and Atmospheric Administration/National Centers for Environmental Prediction Global Forecast; .epw file, Energy Plus weather data; SAMRT, solar adjusted mean radiant temperature. ∗ Corresponding author. E-mail addresses: dragan.milosevic@dgt.uns.ac.rs (D.D. Miloˇ sevi ´ c), ivana b@uns.ac.rs (I.V. Bajˇ sanski), stevan.savic@dgt.uns.ac.rs (S.M. Savi ´ c). is a consequence of the influence of vegetation canopies that cool microclimates by direct shading of the ground surface (Lee, 1978; Oke, 1987). For example, the tree crown can prevent up to 95% of incoming radiation (Akbari et al., 1992). Studies showed that the shading and cooling potentials of parking lot trees are determined by size, growth and spatial arrangement (Bajsanski et al., 2016; Beatty, 1989; National Arbor Day Foundation, 1995; Scott et al., 1999; Simpson, 2002). Noticeable share of the city areas are covered by parking lots occupying from 7% to 30% of its surface (Akbari et al., 1992; Kishii, 2015; McPherson, 2001; Nakamura et al., 2007; Willson, 2013; Wolf, 2004). In the City of Novi Sad (Republic of Serbia), 8% of the area is covered by parking lots. Increase in the number of parking lots is planned for the City in the future in order to fulfill the needs of its growing population (Public Enterprise JP Urbanizam, 2016). In order to improve outdoor thermal comfort, parking lot shading ordinances in cities require up to 50% tree shading over the total paved area (McPherson, 2001). Researchers investigated the influ- ence of trees species (de Abreu-Harbich et al., 2015; Shahidan et al., 2010), growth (Picot, 2004) and changing tree numbers (Andreou, 2013; Taleghani et al., 2016; Yahia and Johansson, 2014) on outdoor thermal comfort in urban areas. The lack of studies on the influence http://dx.doi.org/10.1016/j.ufug.2017.03.011 1618-8667/© 2017 Elsevier GmbH. All rights reserved.